Privacy concerns have already delayed the selection of six test sites that will facilitate unmanned aerial vehicle integration, but key questions still remain.

The Electronic Privacy Information Center, Center for Democracy and Technology, and Rutherford Institute reiterated to the FAA during an April 3 discussion that UAV technology is a bridge beyond traditional aerial surveillance — even as UAV proponents at the same online forum said the FAA should stay out of the privacy discussion.

"We want to be clear, AUVSI does not believe the FAA should govern UAV operations based on privacy issues or concerns," said Ben Gielow, general counsel for the Association for Unmanned Vehicle Systems International. Instead, he argued, the FAA should work with other agencies that have privacy experience. "The FAA should not be in the business of denying access to airspace for anything other than safety reasons."

The unmanned aerial vehicle industry could pump millions of dollars and thousands of jobs into states already chafing from sequestration and looking to inject new funds into their economies.

But the cash influx could leave many members of Congress walking on political minefields as privacy advocates warn of potential infringement by drones, and as the unrelated issue of targeted killing operations by the Pentagon and CIA draws more fire.

Alarmed privacy advocates say UAV technology could be used for nefarious purposes, and even journalists could use it to intrude on the reasonable expectation of privacy.

Commercial UAVs are already being used by law enforcement agencies and by others to forecast the weather, for geological and climate research, and to survey landfills, among other things. The FAA is seeking to gather more information about all those uses as it prepares to issue drone guidelines by September 2015.

The competition for six congressionally mandated test sites has drawn 50 teams from 37 states. Set to be picked by the end of this year, the sites would be able to test the technology for a five-year period.

At the outset of the FAA two-hour online listening session to gather public comments on privacy issues, Jim Williams, who heads the FAA's unmanned aircraft integration efforts, said the agency wouldn't respond to the concerns of each individual caller. But he did say that "there are many questions that must be answered before [the agency] is ready for safe integration."

A coalition that wants to see a drone test site in the San Diego area argues the region already is home to a robust defense industry that regularly partners with private sector companies.

"Unmanned systems could prove critical in how we fight wildfires in the future, which is a very real danger here in San Diego every single year," said Mike Cafferty, president of the San Diego Regional Economic Development Corporation.

In Nevada, backers of a prospective drone test site suggested the state's vast airspace — restricted and commercial — could ease privacy concerns.

With 50 teams looking to win the competitive bidding process, it is difficult to estimate economic gain. But a recent study by the Association for Unmanned Vehicle Systems International estimated that 70,000 new jobs would be created nationwide over three years, growing to 100,000 jobs by 2025. And that could mean as much as an $82 billion economic impact in the United States over a decade.